Across
- 2. a variety of life in an area; usually measured as the number of species that live in an area.
- 3. rain, snow, sleet, or fog with a pH below 7; causes the deteration of forests, lakes, statues, and buildings.
- 5. the field of biology that studies methods and implements plans to protect biodiversity.
- 7. philosophy that promotes letting people use resources in wilderness areas in ways that will not damage the ecosystem.
- 9. programs that release organisms into an area where their species once lived in hopes of reestablishing naturally reproducing populations.
- 13. when members of a species are held by people in zoos or other conservation facilities.
- 14. different environmental conditions that occur along the boundaries of an ecosystem.
- 15. when the last members of a species die.
Down
- 1. the separation of wilderness areas from each other; may cause problems for organisms that need large areas for food or mating.
- 4. damage to a habitat by air, water, and land pollution.
- 6. natural strips of land that allow the migration of organisms from one wilderness area to another.
- 8. a nonnative species in an area; may take over niches of native species in an area and eventually replace them.
- 10. a species in which the number of individuals falls so low that extinction is possible.
- 11. species that have rapidly deceasing numbers of individuals.
- 12. the layer of atmosphere that helps to protect living organisms on Earth's surface from damaging doses of ultraviolet radiation from the sun.